The present invention relates to semiconductor device fabrication and, more specifically, to methods for bonding substrate surfaces, bonded substrate assemblies, and design structures for a bonded substrate assembly.
Silicon-on-Sapphire (SOS) is one of the silicon-on-insulator (SOI) semiconductor manufacturing technologies generally suitable for demanding device applications. An SOS substrate includes an insulating bulk wafer of sapphire and a high-quality device layer of silicon on the insulating bulk substrate. The sapphire substrate virtually eliminates parasitic drain capacitance observed in bulk silicon technologies. A conventional method of forming a SOS substrate is to deposit a thin layer of silicon onto a bulk sapphire wafer at high temperature and may involve epitaxial re-growth of an amorphized surface layer. Silicon is usually deposited by the decomposition of silane gas (SiH4) on a heated sapphire substrate. Device structures are fabricated using the device layer.
Improved methods for bonding substrate surfaces, bonded substrate assemblies, and design structures for a bonded substrate assembly are needed that extend the capabilities of bonded substrate manufacturing technology.